Lumbar support for a chair



FIG. 1 is a rear perspective view of the lumbar support for a chair embodying the new design;

FIG. 2 is a right side view thereof;

FIG. 3 is a left side view thereof;

FIG. 4 is a front view thereof;

FIG. 5 is a rear view thereof;

FIG. 6 is a top view thereof; and,

FIG. 7 is a bottom view thereof.

FIGS. 1-7 show portions of a chair in broken lines. The portions shown in broken lines are for environmental purposes only and form no part of the claimed design. 

CLAIM The ornamental design for a lumbar support for a chair, as shown and described. 